Fix typo in ArrayList.Clone docs (#2098)

very useful update of: grammar in comment

(cherry picked from commit 7e29f22)

plugins/include/adt_array.inc

@@ -74,7 +74,7 @@ methodmap ArrayList < Handle {
 
 	// Clones an array, returning a new handle with the same size and data.
 	// This should NOT be confused with CloneHandle. This is a completely new
-	// handle with the same data but no relation to the original. It should
+	// handle with the same data but no relation to the original. It should be
 	// closed when no longer needed.
 	//
 	// @return              New handle to the cloned array object